钾长石粉酸浸除铁的实验研究

在利用钾长石粉合成沸石分子筛和制取碳酸钾技术中，铁的存在会降低沸石的白度。对北京平谷、天津蓟县、内蒙白云鄂博三地钾长石粉进行硫酸酸浸除铁实验，获得最大铁浸出率分别为88．6％、93．2％和64．6％，且前两地钾长石粉中铁的浸出行为相似，酸浸除铁效果均优于白云鄂博钾长石粉。采用正交实验法研究硫酸浓度、酸浸温度和时间对除铁效果的影响，表明三者对不同地区钾长石粉酸浸除铁效果的影响程度各不相同。钾长石酸浸除铁反应开始时，铁的溶解极快，反应速率主要由化学反应控制；其后溶解相对缓慢，反应速率则由扩散作用控制。

Experimental research into iron removal from K-feldspar powder by acid leaching

When the K-feldspar containing ferric and ferrous impurity is used to synthesize zeolite molecular sieves and to extract potassium carbonate, the ferric and ferrous impurity may decrease the whiteness of zeolite. Iron removal experiments by leaching with sulfuric acids were performed for three K-feldspar powder samples, selected from Pinggu of Beijing, Jixian of Tianjin, and Baiyun Ebo district of Inner Mongolia, respectively. For the K-feldspar powder materials from Pinggu, Jixian, and Baiyun Ebo, the most leaching proportions of iron was 88.6%, 93.2%, and 64.6%, respectively. For the former two K-feldspar powders, iron leaching was performed in a similar way, resulting in a higher efficiency of their iron removals than that for Baiyun Ebo K-feldspar powder. The influential factors for iron removal efficiency, such as sulfuric acid concentration, temperature, and reaction time, were studied with orthogonal experimental method. These factors worked distinctly for K-feldspar powders from different areas. The experimental results also shows that the iron dissolved fast at the beginning of the leaching reaction, and then the corresponding reaction rate slowed down. For these two reaction periods, the reaction rates were mainly governed firstly by chemical reaction, and then by diffusion.